Metastable Folding of Bacillus subtilis glmS Ribozyme Modulates Turnover by RNase J1

Area of Science:

• Molecular Biology
• Biochemistry
• Microbiology

Background:

• Gene expression regulation is crucial for cellular function.
• The glmS mRNA in Bacillus subtilis is regulated by a ribozyme.
• RNase J is a key enzyme in mRNA turnover.

Purpose of the Study:

• To investigate the mechanism of RNase J initiation on glmS mRNA.
• To understand how RNA structure influences RNase J activity.
• To elucidate the role of Mg2+ and co-transcriptional cleavage in mRNA decay.

Main Methods:

• Biochemical assays were used to study enzyme kinetics.
• Single-molecule fluorescence microscopy visualized RNA-protein interactions.
• Analysis of mRNA turnover rates under varying conditions.

Main Results:

• RNase J initiation requires at least 15 unpaired nucleotides at the 5' end.
• Stable ribozyme folding inhibits RNase J, while Mg2+ and co-transcriptional cleavage promote it.
• RNase J processive velocity can exceed transcription speed, potentially leading to polymerase "chasing".

Conclusions:

• mRNA 5' structure stability is critical for RNase J recognition and mRNA half-life control.
• RNase J's activity is finely tuned by RNA structure and cellular conditions.
• This mechanism provides insights into post-transcriptional gene regulation in bacteria.